Background: There is a high prevalence of chronic disease in Saudi Arabia. In fact, it is a leading nation in the world when it comes to chronic diseases. Many people use complementary and alternative medicine (CAM) to treat various conditions in different regions of Saudi Arabia. Material and Methods: An online survey was used for this cross-sectional study. The sample included 500 patients with chronic diseases in Saudi Arabia. Data were collected on participants’ sociodemographic information, knowledge about CAM and their sources of that knowledge, and attitudes toward CAM practices. Results: Of the participants, 83.8% were females and 16.2% were males. A majority (62.6%) had some knowledge about CAM, which they acquired from the Internet (24.8%) and family (20%). On the other hand, 37.4% lacked any knowledge of CAM. Hijama and herbal medicine are used equally (21.8%). Regarding participant satisfaction with CAM treatments, 271 reported feeling good, while 218 did not know. Conclusion: The outcome of this cross-sectional study showed that 62.6% have knowledge of CAM and 76.6% use it, either alone or in combination with modern medicine. Our findings in this study may guide the direction of future research and have practical implications for family practitioners treating patients with chronic diseases.